Do we really need a gigabit LAN?

When we install our systems and services, organizations tell us that they want to move to a gigabit LAN. Motives vary, and as an engineer I always like to know what problem they’re trying to solve by going to a gigabit LAN. We hear things such as:

We want to take this opportunity to future-proof our office.

Our IT provider tells us we should do it.

We want to make sure we have the capacity to run both voice and data on the LAN.

We’ve been told that it’s the new “standard.”

Our services are slow so we need to go to a faster LAN to speed them up.

The reality is that most organizations we work with who ask about gigabit LANs don’t really need one, and won’t for the foreseeable future. Many organizations experiencing problems they hope a gigabit LAN will solve, are disappointed to find that the bottleneck was never in the LAN and they’re still no further ahead, or that the bottleneck has moved somewhere else and they now have a new set of problems to deal with.

This isn’t to say that gigabit LANs are not needed. It’s just that many people who think they need one should take a closer look to see if it will really deliver what they hope it will before they make the investment. Organizations working with large design or media files, software development houses, sites with large server farms, etc., almost certainly would benefit from a gigabit LAN.

I don’t want to throw our IT friends and colleagues under the bus, but most IT people I’ve run across tend to be very good at managing desktops and servers, and pay less attention to network design. Faster isn’t better if it’s applied where it’s not needed, or if it’s not done as part of a more comprehensive look at the overall traffic flow. Let’s look at a Network 101 level of traffic engineering.

One of the best examples of a network can be found in nature. Consider a tree. At the extremities, both roots and leaves, are fine capillary structures that grow in size and capacity as they move toward the trunk and accumulate more branches along the way. Desktop workstations are essentially these kinds of extremities, and generally have the lowest bandwidth requirements. As you move toward the access point for your LAN, the backbone of your network needs to have the capacity to aggregate all that traffic. Most 100Mb/s switches have 2 or 4 gigabit ports on them for inter-switch connectivity, and shared servers for exactly this reason.

An often overlooked item is the bandwidth of the access service. If you do offsite backup or use cloud-based services, you need to ensure adequate bandwidth in both directions (download and upload) of your access service. Symmetric services, such as fibre or cable modem services, are called for in such instances. Technologies such as DSL are asymmetric, with far less upload bandwidth than download bandwidth, and are not suited to cloud-based services.

And last, but not least, not all cloud service providers lay on enough resources (bandwidth, processing, etc.) to support fast changing levels of demand. We have on several occasions run bandwidth capacity tests on fibre services that show rated capacity is available, yet some unfortunate customers continued to experience suboptimal data rates to/from their cloud services. Since bluArc runs on a managed network, we have observed that data rates from such sites improve, sometimes suddenly and sometimes over several months, with no changes in our network or the customer site. Care to guess what changed? The far end provider!

If you’re having a problem with slow response on your network, you would be well advised to get the help of an experienced network tech to help diagnose the problems and locate the bottlenecks in your services before throwing money at LAN bandwidth. While access can often be a bottleneck, it isn’t always the culprit either. Once you know what problem you’re trying to solve, you’ll be in a better position to judge whether a gigabit LAN is worth the investment.